docs: def flush(self, indices=None, refresh=None):
          """
          Flushes one or more indices (clear memory)
          If a bulk is full, it sends it.
  
          (See :ref:`es-guide-reference-api-admin-indices-flush`)
  
  
          :keyword indices: an index or a list of indices
          :keyword refresh: set the refresh parameter
  
          """
          self.conn.force_bulk()
          path = self.conn._make_path(indices, '_flush')
          args = {}
          if refresh is not None:
              args['refresh'] = refresh
          return self.conn._send_request('POST', path, params=args)